Filter assemblies comprising pleated media packs disposed in a frame structure are known. A pleated filter pack is typically formed from a sheet of filter media, e.g. a fiberglass sheet, or a nonwoven polyester sheet, which is pleated to increase the effective filtering area of the filter body. To provide mechanical support and/or to combine a plurality of media packs, the media pack is typically arranged in a frame structure, such as a frame having a V-type arrangement. In order to enhance the physical properties of pleated filter media, it is known to provide different types of support elements thereto such that deflection during use of the filter media can be reduced. Deflection can in a worst case scenario lead to a break of the filter media. But even if it does not come to a breakage of the filter media, deflection thereof causes adjacent media packs to come closer to each other or even come in contact. Both events lead to an increase in pressure drop over the filter since the air cannot flow as intended through there. One example of support is shown in WO-2010/151542 where a flexible but inextensible scrim is attached to a downstream surface of a filter media. While the use of such scrim has advantages over the use of a filter media with no backing at all and prevents deformation of the filter media to a certain extent, it still has some disadvantages. For example, since the scrim is attached to the pleats of the filter media itself, the forces acting on the scrim will be transferred to these pleats which, if it comes to the worst case, may burst thus ruining the filter media.